phrases - Simpler and more common way of asking "Where could he/she had gone?"

I'm not a native English speaker, and I though asking "Where could he/she had gone?" was very common. But when I searched that phrase in Google I got only 6 results.

Is there a more simpler, more common way of asking that question?

Answer

You got only 7 hits because you have the ungrammatical “could had gone” instead of the correct “could have gone”. If you fix your had into a have, it will be fine.